Passing Data from App delegate to View Controller

Question

I need to Pass an string from App delegate to my Initial View Controller , Can somebody listed me the best way to do it , also i tried to Save and Retrieve using NS user Defaults, but i doesn't work out properly .

Answer 1

Interface:

@interface MyAppDelegate : NSObject  {   NSString *myString; } @property (nonatomic, retain) NSString *myString; ... @end 

and in the .m file for the App Delegate you would write:

@implementation MyAppDelegate @synthesize myString;     myString = some string; @end 

Then, in viewcontroller.m file you can fetch:

MyAppDelegate *appDelegate = (MyAppDelegate*)[[UIApplication sharedApplication] delegate]; someString = appDelegate.myString;  //..to read appDelegate.myString = some NSString;     //..to write 

Answer 2

Here it is for Swift:

View Controller

let appDelegate = UIApplication.sharedApplication().delegate as AppDelegate 

Furthermore, if you have an object that you want to pass between view controllers (for example, I had CloudKit data I wanted to share) add this to the App Delegate:

    /* Function for any view controller to grab the instantiated CloudDataObject */ func getCloudData() ->CloudData{     return cloudDataObject } 

Then back in the View Controller

var model : CloudData = self.appDelegate.getCloudData() 

Answer 3

You can access your root view controller like this from the app delegate:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    MyViewController* mainController = (MyViewController*)  self.window.rootViewController;
    [mainController passData:@"hello"];

    return YES;
}